It’s so common to throw out food that we rarely stop to consider that it’s a huge waste of money. “Slippage” is an economic term for the difference between the estimated costs of a transaction and what you actually pay. When it comes to food, “slippage” is when you buy bananas, eat three, and throw away two. Stop now and save big.

1. Figure out what you use frequently and buy it — and only it — in bulk.

Everyone knows their staples: cereal, coffee, toilet paper — anything your family always has on hand or might make a special trip to buy. These are the only things you should ever buy in bulk at wholesale stores or discount clubs.

2. Make a meal plan and a grocery list — and stick to them.

Your list can be definite while your meal plan is hazy. Say you know you’re going out Friday and have something already for Monday but still need to cook Tuesday, Wednesday, and Thursday. Choosing the actual meat or vegetable or pasta can depend on what might be on special at the store, but you’re still sticking to your list in terms of basic items to acquire.